WASHINGTON — Millions of Americans suffered a loss of wealth during the recession and the sluggish recovery that followed. But the last half-decade has proved far worse for black and Hispanic families than for white families, starkly widening the already large gulf in wealth between non-Hispanic white Americans and most minority groups, according to a new study from the Urban Institute.

“It was already dismal,” Darrick Hamilton, a professor at the New School in New York, said of the wealth gap between black and white households. “It got even worse.”